1. Field of the Invention
The present invention relates to perfluoroalkylenetriazine polymers and more particularly to a new method for preparing them.
2. Description of the Prior Art
Perfluoroalkylenetriazine polymers have been prepared heretofore by two different methods, namely the acylationcyclodehydration of imidoylamidines and the free radical coupling of preformed triazine derivatives. However, these polymerization methods have so far yielded polymer specimens that show disappointing material properties [Fluoropolymers, High Polymers Volume XXV, edited by Leo A. Wall, Wyley-Interscience (1972), pages 267 to 289 and 307 to 315; hereafter cited as Fluoropolymers]. In the case of the first and most intensively investigated method, the imidoylamidine approach, it has generally been found to be "very sensitive to reaction conditions, afford poor reproducibility, and yield polymers of molecular weights only marginally high enough for good physical properties". (Fluoropolymers, page 288.) In fact, this approach is said to fail "because the ammonia liberated during cyclization causes reorganization reactions, randomizing the assimilation of mono- and difunctional compounds into triazine rings, altering the functionality of the reaction system, and leading to undesired cross-linking and shortened chains". (Fluoropolymers, page 276.) As to the second method, coupling of preformed triazine rings, synthetic difficulties and poor reactivity have led to polymers that are not elastomeric at room temperature, due to the shortness of the chains between the triazine rings (Fluoropolymers, page 280). In the circumstances, the principal object of the present invention is to provide a method that overcomes some of the shortcomings of the prior art and yields triazine polymers that are elastomeric at ambient temperature.